Tachymetric correcting device, more particularly for use in connection with sighting apparatus for artillery



.J. FIEUX 2,106,998 TACHYMETRIC CORRECTING DEVICE, MORE PARTICULARLY FOR USE IN CONNECTION WITH SIGHTING APPARATUS FOR ARTILLERY 4 Sheets-Sheet l Filled Feb; 14, 1936 2,106,998 FOR USE Feb. 1, 1 FiEUX TACHYMETRIC CORRECTING DEVICE, MORE PARTICULARLY IN CONNECTION WITH SIGHTING APPARATUS FOR ARTILLERY 4 Sheets-Sheet 2 Filed Feb. 14, 1956 Unv n for eam/ m AHvnzef/s Feb. l, 1938. 1 FIEUX 2,106,998

TACHYMETRIC coEREcTING DEVICE, MORE PARTIGULARLY FOR UsE ARATUS FOR ARTILLEEY IN CONNECTION WITH SIGHTING APP Filed Feb. 14, 1936 4 Sheets-Sheet 3 lik USE SheetYs-Sheet 4 Feb. l, 1938.

J. FIEUX DEVICE, MORE TING AP eb 14 PARTICULARLY FOR PARATUS FOR ARTILLER TACHYMETRIC CORREGTING IN CONNECTION WI SIGH `edF.

Patented Feb. l, 1938 TACHYMETRIC CORRECTIN G DEVICE, MORE PARTICULARLY FOR USE IN CONNECTIGN SIGHTING. APPARATUS FOR ARTIL.-

.llean Fieux, Paris, France, assigncr ci one-half to Schneider & Cie, Paris, France, a jointstock company of France Application February 14, 1936, Serial No. 63,934

In France April 4, 1935 14 Claims.

It is known that correcting devices are available intended more particularly for receiving the Variable data for firing at a moving objective such as an aircraft. The use of these devices, however, introduces into a. re control system a very considerable complication, not only from the point of View of their construction and manufacture but also and above all due to the fact of the numerous personnel which they require for their superintendence or manipulation. As a rule, these known devices necessitate attendants who receive, by the indications transmitted to them, the data of the corrections to be worked out, and who introduce the data 'thus furnished into the complicated mechanism intended for working out the final correction, which may be the sum or the ,product or both the sum and the product of a certain number of elementary data. The correction-combining device is in a manner a calculating machine'which only works out the corrections by the intervention of a relativelylarge number of attendants constantly engaged in bringing the members of the device as a whole into positions corresponding to the variations of the .firing data or in maintaining the said members in those positions.

Among the corrections which it is indispensable to take into consideration, there is above all the correction resulting from a variable angular velocity which is taken into consideration outside the correcting/device proper by the variations in position impressed by a gunner upon a sighting device with which he follows the evolutions of the objective.

While involving, of course, a device which may be termed an angular tachymetric device, that is, one requiring the intervention of an attendant or pilot for keeping a sighting device directed on the objective, the invention, apart A40 from the said control between the said observer and the objective, practically only comprises mechanical means which render the whole of the correction combining devicev automatic inthe true sens'e and dispense with the considerablel number of attendants required by the devices known heretofore.

Of course, the considerable simplification proaircraft.

Therel is nothing to prevent the conception of (Cl. 35i-Q1) the combination of this correcting device with additional correcting means for receiving and transmitting corrections such as those for the wind or drift, necessitated for example by firing from a gun mounted on the ground or on board a ship.

According to the invention, this result is obtained by the mechanical connection of the device for the continuous observation of the movable objective, the sighting telescope for example, and a gyroscope, the variations in position impressed upon the said gyroscope being transmitted to a very sensitive intermediate device, such as a pressure-reducing device for fluid, acting in its turn upon a receiving servo-motor connected to the member the position of which is nally to be corrected, such as a gun laying indicator or even the gun itself. There is thus provided a practically direct connection between the member to be moved by an observer and the member whose position is to be corrected, due to the interposition of a gyroscopic device and a transmission by a uid, the pressure of which is at any instant a function of the reaction of the said gyroscopic device.

Practically, the simplified tachymetric correcting device comprisesa servo-motor for receiving the corrections the latter being transmitted by a fluid subjected to a pressure undergoing variations which are a function of the total tachymetric correction, the said variations being themselves impressed upon one of 'the faces of the movable member of a pressure-reducing device, by the casing of a gyroscope connected'to the telescope, the said pressures being at any in-l stant equilibrated on the opposite face of the said movable member, so that the movement of the piston or other movable member of the servo-motor received from an appropriate distributor is a function ofthe equilibrating pressure.

This simple device wherein the variationsin position of the telescope are finally expressed as a variable thrust of the casing of the gyroscope on one of the faces of a member, the opposite face whereof is subjected at any instant to a reaction equal and opposite to that of the thrust, creates in a manner a static transmission system for a variable energy as a function of the variation in position of the telescope.

To simplify thedescription, the pressure-reducing device which is subjected to gyroscopic reactions will be termed transmitter, while the whole of the servo-motor and its distributor sensitive to the variable equilibrating pressure emanating from the transmitter, will be termed the "receiver.

In practice, the pressure-reducing and equilibrating device will on its external face be subjected to the action of a spring, of adjustable force, acting on the' equilibrating device preferably through the medium of the casing of the gyroscope.

A description of different transmitters and a receiver employing the means according to the invention is given hereinafter by way of example.

A rst form of construction is shown in Figures 1 to 7, inclusive, of the accompanying drawings.

Figure 1 shows in sectional elevation a transmitter acted upon by the angular velocity impressed upon the suspension frame of a gyroscope which frame is also operatively connected to a target observing telescope in such a manner as to move therewith in azimuth. The same iigure also shows in axial section an appropriate receiver the movable member of which is adapted for connection to the member whose position is to be corrected. It likewise shows the diagram of the pipe lines connecting the transmitter to the' receiver.

Figures 2 and 3 are-respectively partial sections of the receiver along the lines II-JI and III-III in Figure 6.

Figure 4 is an external view of the transmitter shown in section in Figure 1.

Figures 5 and 6, respectively, cross-sections of the receiver along the lines V-V and VI-VI in Figure 1.

Figure 7 is a longitudinal section of the servo# motor along the line VII-VII in Figures 1, 5, and 6.

Figures 8 and 9 show in elevation and plan, respectively, a modiication employing a double transmitter, the base and suspension frame being shown sectioned by planes passing through the axis of the elevating trunnions of the suspension frame. l A

Figure 10 is a partial section along the line X-X in Figure 8.

Figure 11 shows in sectional elevation a double transmitter, wherein the rotor is adapted to be subjected to considerable and rapid variations' in speed.

Figure 12 .is'a partial section along the line X11- XII in Figure l1.

Figure 13 is a partial section along the line XIII-XIII in Figure 11.

l Figure 14 is a diagram of the electrical connections relating to the control of the speed of the rotor shown in Figure 11.

The device shown in Figures 1 to 7 comprises a gyroscope constituted in known manner by a rotor I revolving in a casing4 2 suspended from a frame 3 by trunnions 4 and 4 along a horizontal' axis perpendicular to the axis of the rotor. I'he frame 3 is operatively connected in any suitable manner to a target observing telescope so as to move therewith in azimuth about a vertical axis perpendicular to both the axis of trunnions 4, 4 and the axis of rotor I. For example, a telescope 96 may be mounted on the frame 3 in the manner indicated in Figures 1 and 4 so as to move with the frame in azimuth but relatively thereto in elevation. A boss 5, integral with the casing 2, receives on one side thereof the pressure of a spring 6 which bears by its other end against an adjustable seat 1 carried by the frame 3. A push rod 8 engages the other side of the boss 5 and operatively connects the same to a piston pressure-reducing device 9 moving ina cylindrical housing provided in the frame 3 and closed by an end I0 which carries a stop II. A circular groove I2 provided in the piston 9 is put into communication by means of a certain number of orifices I3 with the chamber closed by. the base I0 and called the expansion chamber of the transmitter. The wall of the cylindrical housing includes two circular grooves I4 and l5 separated from one another by a partition of a thickness substantially equalto the width of the groove I2 in the' piston. The said grooves I4 and I5 are in communication respectively with thepipe lines I6 and I1. Furthermore, a pipe line I8 including a. throttling diaphragm I9 puts the expansion chamber into communication with another chamber called the manometric chamber provided in a frame 20 forming the casing of the receiver and bounded by a 'fixed end 2I and also by-a. pilot piston 22 and a control sleeve 23. The said sleeve is secured to a driving rod 24 and a driving or motor piston 25 by means of a driving finger 26 while the driving rod 24 isoperatively connected in any suitable manner with the member whose position is to be corrected to compensate for the probable change of position of the target during the time of ight of the projectile as indicated bythe angular velocity of the target observing telescope. For example, the rod 24 may be connected to a rack member 91 with which is engaged a pinion 98 mounted on a shaft 99 constituting the input to one side of a differ? ential gear arrangement |00. The shaft IUI constituting the input to the other side of the differ-l ential may be actuated in any suitable manner to indicate the bearing of thev target. 'Ihe output gear |02 of the diierential may then be driv- I ingiy connected to the pointer of a suitable indicator ID3 in known manner, whereby said pointer indicates the bearing 'of the target corrected to compensate for its probable change of position during the time of ight of the projectile. 'I'he pilot piston 22 includes two circular grooves 21 and 28 in correspondence with the intermediate portions separating three circular grooves 29, 30, and 3l provided in the sleeve 23. The grooves 29 and 3I communicate respectively with longitudinal grooves 32 and 33 (Figures 2 and 3), which in their turn communicate respectively through orices 34 and 35 with a discharge chamber 36 providedin the casing 20 and closed by a cover 31. The piston 25 moves in aA cylinder, the two working chambers 38 and 39 of which are put into communication respectively, through the medium of the pipe lines 4i! and 4I, the grooves 42 and 43 and the orices 45 and 44,.with the grooves 21 and 28, respectively of the pilot piston 22. The latter is connected by means of a push rod 46 to a swing-bar 41 connected to the frame 20 by two springs .48 and 49. An oil pump 50 draws oil from the chamber 36 through a pipe line 5I and delivers it into the pipe line I1. The chamber 36 is furthermore in free communication with the pipe line I6. Finally, in the pipe line I8 is disposed a manom-eter 52 having its graduated scale symmetrical with respect to the zero which corresponds. substantially to the mean position of the pointer on the dial.

In the transmitting device shown in Figures 8, 9, 10, the casing'2 of the gyroscope is suspended by horizontal trunnions 53 and 53' from a frame 54, which in turn is 'suspended by vertical trunnions 55 and 55' from an oscillating support 56, Which is adapted to be aimed Jin elevation relatively to a xed frame 51 as well as trained in azimuth with said frame to follow the movements of the target observing telescope |04' which in this instance may be carried by said support. For this purpose the frame 51 is provided with horizontal trunnions 58 and 58' on which the support 56 is rotatably mounted. 'I'he frame 51 also includes cylindrical housings, the axis of which coincides with the axis of the elevating trunnions 58 and 58' and in which move pressure-reducing pistons 9 and 9' identical with the pressure-reducing piston of the device previously.

described. 'Ihe piston 9 is connected to the casing 2 by means of a push rod 59, an intermediate shaft 60, a push rod 6I and a boss 62 secured to the casing 2. 'I'he said boss receives the pressure of a spring 63 bearing on an adjustable seat 64 secured to the oscillating support 56. The piston 9' is connected to the frame 54 by means of a push rod 59', an intermediate shaft 65 and a connecting rod 66. 'I'he frame 54 carries a boss 61 whichreceives the pressure of a spring 68 bearing on an adjustable seat 69 secured to the oscillating support 56. On the latter. are pivoted the shafts 68 and 65 respectively by the pivots 18 and 18' and the pivots 1I and 1I'.

In the transmitting device shown in Figures v11, 12, 13, and 14, a rotor 12 is journalled in a casing 13 which in turn is journalled in a frame 14 along a horizontal axis exactly as, in the device shown in Figures 8 and 9, the casing 2 is joumalled in the frame 54. 'I'he frame 14 is pivoted by means of vertical trunnions 15 and 15 to a frame 16 which carries the target observing telescope |85 and an electric motor 11 coupled to the rotor 12 by means of a balanced lever 18 and push rods 19 and 19' disposed substantially in the plane of the two axes of suspension of the casing 13. The. pressure-reducing pistons 9 and 9' identical with the pressure-reducing pistons of the preceding devices, are adapted to move in cylindrical housings provided in the frame 16. 'I'he piston 9 is connected by a push rod 80 to the casing 13 which receives the pressure of a spring 8i bearing on an adjustable seat 82 secured to the frame 16. The piston 9' is connected by a push rod 83 to the frame 14 which receives the pressure of a spring 84 bearing on an adjustable seat 85 secured to the frame 16. The motor 11 isof the series type with reversal of the torque and comprising two eld windings 86 and 81. It actuates a centrifugal governor which by means of a slide 88 and push rod 89 acts upon a contact lever 90 pivoted to the frame 16. The lever 98 also receives the antagonistic action of a push rod 9| actuated by a piston 92 moving in a cylindrical housing of the frame 16 and receiving the controlled pressure of a fluid through a pipe line 93. The pressure of the fluid in pipe line 93 may be varied in any suitable manner as a function of some other factor entering into the re control, such as the range of the objective or target. Suitably insulated to serve as an `electrical conductor, the lever 98 is adapted to oscillate between two contacts 94 and 95 Which allow the currents to pass into the fleld windings 81 and 86, respectively.

Insystems utilizing transmitters of the forms shown in Figures 8-10 and 11-14, whereby corrections in both azimuth and elevation may be derived from a single gyroscope suspended in a frame having two degrees of freedom, there are also provided twin receivers identical with that shown in Figures 1-7, the movable or motor elements of said receivers being operatively con-Y nected in any suitable manner to the members 1 controlling the laying of the gun in azimuth and A elevation, respectively.'

The various devices described hereinbefore operate as follows:

The pressure-reducing piston 9, or pistons. 9 and 9', ensure the distribution of the iluid forced by the pump 50 through the pipe line I1 under a predetermined pressure. A lower pressure is established in the expansion chamber, automatically equilibrating the action of the push rod acting directly on the said pressure-reducing piston. By means of the pipe line I8, the pressure established in the expansion chamber is transmited .to the manometric chamber and produces a thrust on the pilot piston 22, which always ilnds a position of equilibrium for a certain exion of the springs 48 and 49.

'I'he pipe line I6 serves to dischargev the uid from the expansion chamber, when, due to a drop in pressure, the volume of the manometer chamber diminishes and a portion of the liquid ccntained in the latter is forced through the pipe line I8 towards the said expansion chamber.

The result of this is that the movement of the pilot piston 22 relatively to the frame 20 is pro' portional to the thrust transmitted by the push rod of the pressure-reducing piston 9 or 9', and that, by means of the sleeve 23, the control rod v24 is itself moved.- proportionally to the said! thrust, irrespective of the resistance oered by the member to be operated.

In the device shown in Figures 1 to 7, the push A f rod 8 transmits the resultant of the pressure of the spring 6 and the tangential force produced by the reaction offered by the rotor I of the gyroscope l(the velocity of which is assumed to be constant) .to the movements in azimuth impressed upon the observation telescope which is operatively connected to the suspension frame 3. As is known, the said reaction is proportional to the angular velocity w of the frame 3 about an axis perpendicular to the plane formed by the axis of the rotor and the line of the trunnions 4-4. When the said velocity w is zero, the push rod 8 is only subject on the one hand to the constant calibration pressure of the spring 6, and on the other hand to the pressure in the pipe line I8, which then has a well-deterxnined value, for which the pointer of the manometer is at" the zero of the scale, while the driving piston 25 is at the zero correction position corresponding to a likewise predetermined flexion of the springs 48 and 49. When the gyroscopic reaction is not zero, the tangential force on the push rod 8 is added algebraically to the tension of the spring 6. This results in a movement of the pistons 22 and 25 relatively to their normal or zero correction posi-v tion, the said movement being proportional to the angular velocity w and being in the same sense as the said velocity.

In the device of Figures 1 7, the operation of which has just been described, the gyroscope is suspended from the support 3 along one axis only, defined by the line of the trunnions 4 and 4', which in a manner connect the casing! and the said support 3 in the movement of angular velocity w, but which, however, allow the piston 9 to move freely for playing its part as distributor with all the necessary sensitivity.

In the devices shown in Figures 8, 9, 10, 11 and 12, the gyroscope is suspended from the support 56 or 16 by means of a frame, that is to say along two axes of pivoting. It can no longer'be con- Y sidered as being positively connected 'tothe said .the use of flexible pipe lines.

an axis perpendicular to the axis of the rotor. Actually, however, the liquid of the pressure-reducing chambers forming a check on the pistons 9 and 9' ensures a suil'icient connection to drive the casing in the angular movements of the support, while being sufficiently exible to permit of the relative movements of very small amplitudes normally imposed by the operation of the pressure-reducing devices.

It should be noted furthermore that the incompressibility and the viscosity of the liquid oppose the establishment of any resonance between these small relative movements which consequently cannot in any case be developed and give rise to nutations, that is to say irregular movements of the gyroscope. It is therefore possible according to the invention to-construct a double transmitter while employing a single rotor, each of the two pressure-reducing devices being in communication with a receiver similar to that .which has been described hereinbefore.

When a transmitter is constructed to permit of elevation of the support frame (Figures 8 and 9), it is advantageous to place the pressure-reducing devices on the fixed frame in order to obviate In that case, the special rod gear described hereinbefore is employed for the transmission of the-mechanical thrusts on the pressure-reducing pistons 9 and 9. The push rods 59 and 59' being disposed along the geometric axis of the trunnions 58 and 58', any untimely action on the said pistons during the .elevation of the movable support 56 is obviated.

VIn the device shown in Figures 11, 12, 13, and 14, means are employed for varying the speed of the rotor 12 as rapidly as is necessary without producing on the suspended system any reactions capable of being combined with the gyroscopic reaction proper, and consequently capable of introducing inadmissible disturbances in the operation of the pressure-reducing devices. It is certain, on the one hand, that the coupling constituted by the lever 18 and the push rods 19 and 19' cannot in practice either create or transmit any untimely action on the said suspended system. It is equally certain, on the other hand, that being rigidly fixed to the frame 16, the motor 11 may, without inconvenience and by simple means, be given an external mechanical action .for modifying its feed. Thus, the push rods 89 and 9| acting in opposition on the contact lever 90 may be actuated with all the necessary force. If the distribution by the said .lever affects the total feed current, in accordance with the diagram shown in Figure 14, there is obtaineda very high torque in onec sense or the other, capable of imparting to the rotor at any instant a predetermined speed depending upon the distance of the objective.

By creating a loss ot head in the pipe line I8, the diaphragm I9 constitutes a very simple means of reducing the amplitude of the oscillations of the pilot piston 22 and all the more of the oscillations of the driving piston 25 which correspond to the irregularities of the angular velocity w, generally due to the unavoidable irregularities of the aiming velocity. By the effect of the said diaphragm, the volume of the manometrlc chamber can only vary slowly. The result thereof is practically that the correcting device. instead of being influenced immediately at any instant by the changes in position more' or less regularly impressed upon the telescope, remains sensitive only to the mean angular velocity of the support of the gyroscope, that is to say, to

the only velocity which is to be considered for the determination of the corrections.

In all the forms of constructions which have just been described, the pressure controlled by 'the transmitter or transmitters determines the position of the receiving pilot member and hence the position of the member of the servo-motor effecting the desired correction. 'I'his pressure is transmitted by a pipe line, the delivery of which is low enough for the loss in head therein to be negligible. 'Ihis pipe line therefore provides between the transmitter and the receiver, which may be some distance apart, a transmission of sufficient precision and of convenient installation. Y

Furthermore, if a liquid is employed, that is to say, a uid of very low compressibility (water. oil and the like) to reduce to a minimum the effects of elasticity in the conduit, it is possible,l as stated hereinbefore, to employ asingle gyroscope for determining the corrections in two perpendicular plan'es (training correction and elevation correction). The .transmission liquid acting on the pistons of the two pressure-reducing devices constitutes a check, suflcient to prevent the initiation or at least the excessive development of nutation movements, but nevertheless ensuring the necessary and adequate angular connections between the gyroscope and its suspension frame.

Among the means covered by the present invention, provision is also made for varying the speed of the rotor in order to obtain corrections proportional not only to a certain component w of the angular velocity of the suspension frame, but to the product of the said component multiplied by another variable factor, such as the duration t of flight of a projectile or a certain function of the said duration.

An important advantage of the invention de,- scribed is also to be seen in the fact that use is made of a motor of suilicient power flxed to the suspension frame of the gyroscope and not, as is usual, to the actual casing of the rotor for imposing on the latter the said variation in velocity with all the necessary rapidity. The rotor and the shaft of the motor being connected by a special coupling lend themselves freely to the throw- Y ing out of centre of the one relatively to the other. Due to such an arrangement, it is possible, as set forth hereinbefora to. act by convenient means on the speed governor of the motor without creating any disturbance in the operation of the transmitter.

It 1will be appreciated that, without any prejudice to the exact and continuous transmission of the tachymetric corrections, it is possible to employ the devices described for causing them to' transmit other or additional corrections, such as corrections for wind, drift and so forth. One means may consist, for example, in an appropriate action on the calibration springt, the support of which on the frame 3 may for this purpose be rendered movable according to a predetermined law.

While three different forms `of` the invention have been described and illustrated in the accompanying drawings, it will be obvious that the invention is not limited to the exact structure shown but is capablev of a variety of mechanical embodiments. Various changes, which will now suggest themselves to those Vskilled in the art, may be made in the form, details of construction and arrangement of the parts without departing from the spirit of the invention.

Reference is therefore to be had to the appended claims for a deiinition of the limits of the invention.

I claim:

1. A tachymetric correcting device for use in gunnery re control systems in combination lwith a target observing telescope and an element of the gun laying ymechanism whose position is to be corrected to compensate for the probable change of position of the target during the time of iiight of the projectile, comprising a suspension frame operatively connected with the observing telescope to move therewith atleast in azimuth, a

gyroscope having its casing pivotally mounted inl said suspension frame on an axis at right angles to the axis of rotation of the gyroscope rotor, a uid operated servo-motor device v operatively connected to the element whose position is to be corrected, means controlling the supply of iiuid to said servo-motor device including a movable member subjected on one'side to the pressure of the iluid supplied to said controlling means, and means for transmitting tothe, other sideof said member the thrust exerted by said gyroscope casing in attempting to precess about its pivotal axis in said suspension frame upon movement of said frame in azimuth.

2. A tachymetric correcting device for use. in

gunnery re control systems in combination with a target observing telescope and an lelement of the gun laying mechanism whose position is to be corrected to compensate for the probable change of position of the target duringv the time of flight of the projectile, comprising a suspension frame operatively connected with the observing telescope to move therewith at least in azimuth, a gyroscope having its casing pivotally mounted in said suspension frame on an axis at right angles to the axis of rotation of the gyroscope rotor, a fluid operated servo-motor device operatively connected to the element whose position is to be corrected, means controlling the supply of iiuid to said servo-motor device including a movable lmember subjected on one side to the pressure of the fluid supplied to said controlling means, means for transmitting to the other side of said member the thrust exerted by said gyroscope casing in attempting to precess about its pivotal axis in said suspension frame upon movement of said framein azimuth, and adjustable means for modifying the thrust thus created by said attempted precession of the gyroscope.

3. A tachymetric correcting vdevice for use in gunnery re control systems in combination with a target observing telescope and an element of the gun laying mechanism whose position is to be corrected to compensate for the probable change of position of the target during the time of ilight of the projectile, comprising a suspension frame operatively connected with the observing telescope to move therewith at least in azimuth, a gyroscope having its casing pivotally mounted in said suspension frame'on an axis at right angles to the axis of rotation of the gyroscope rotor, a fluid operated servo-motor device operatively connected to the element whose position is to be corrected, means controlling the supply of iluid to said servo-motor device including a movable member subjected on one side to the pressure of the fluid supplied to said controlling means,

means for transmitting to the other side of said member the thrust exerted by said gyroscope casing in attempting to precess about its pivotal axis in said lsuspension frame upon movement of said frame in azimuth, a compression spring positioned between said suspension frame and said each of the training and elevating gun laying. mechanisms whose position is to be corrected tocompensate for the probable change of position of the target during the time of night of the projectile, comprising a suspension frame operatively connected with the observing telescope to move therewith in both azimuth and elevation, a gyroscope mounted in said suspension frame for movement about two axes at right angles to one another and to the axis of rotation of the gyroscope rotor, a pair of fluid operated servo-motor devices operatively connected to the elements whose positions are to be corrected, means controlling the supply of fluid to one of said servomotor devices including a movable member subjected on one side to the pressure of the fluid supplied to said controlling means, means for transmitting to the other side of said member the thrust exerted by the gyroscope in attempting to precess about one of its axes of freedom upon movement of said suspension frame in azimuth, separate means for controlling the supply of fluid to the other of said servo-motor devices including a second movable member subjected on one side to the pressure of the fluid supplied to its' associated controlling means, and means for transmit-'- ting 'to the other side of said second movable member the thrust exerted by the gyroscope in attempting to precess about its other axis of freedom upon movement of said suspension frame in elevation.

5. A tachymetric correcting device for use in gunnery fire control systems in combination with a target observing telescope and an element of each of the training and elevating gun laying mechanisms whose position is to be corrected to compensate for the probable change of position of the target during the time of flight of the projectile, comprising a suspension frame operatively connected with the observing telescope to ,move therewith in both azimuth and elevation, a gyroscope mounted in said suspension frame for movement about two axes at right angles to one another and to the axis of rotation of the gyroscope rotor, a pair of uid operated servo-motor devices operatively connected to the elements Whose positions are to be corrected, means controlling the supply oi'- uid to one of said servomotor devices including a movable member subjected on one side to the pressure of the fluid sup- `a second movable member subjected on one side to the pressure of the fluid supplied to its associated controlling-means, means for transmitting to the other side of said second movable member the thrust exerted by the gyroscope in attempting to precess about its other axis of freedom upon movement of said suspension frame in elevation, and springs operatively interposed between said suspension frame and those points of said gyroscope mounting at which the said thrusts due to 76 precession are exerted on said transmitting means.

6. A tachymetric correcting device according to claim 4 including a supporting member on which said suspension frame is pivotally mounted on a horizontal axis laterally olf-set from the horizontal axis of freedom of the gyroscope, said two controlling means'also being mounted on said supporting' member, and wherein each of said thrust transmitting means includes a rod substantially coaxial with said horizontal axis on which the suspension frame is pivotally mounted.

7. A tachymetric correcting device according to claim 4 including a supporting member having a pdr of horizontal trunnions laterally off-set from the horizontal axis of freedom of said gyroscope and forming a, pivotal mounting for said suspension frame, housings carried by said supporting member coaxial with said trunnions in which the movable members of said two controlling means are housed, and a pair of rods coaxial with said trunnions constituting portions of said two thrust transmitting means.

8. A tachymetric correcting device according to claim 1 including a motor for driving the rotor of said gyroscope xed with respect to -sald suspension frame, and a flexible coupling between said motor and rotor so constructed and arranged that the rotor may move out of axial alignment with the motor shaft without adversely affecting the driving connection therebetween.

9. A tachymetric correcting device according to claim 1 including a governor device for automatically controlling the speed of rotation of the gyroscope rotor, and means for modifying the controlling eiect of said governor device in accordance with variations in the range of the target. Y

10. A tachymetric correcting device according to claim 1 including a governor .device for automatically controlling the speed vof rotation of the gyroscope rotor, 4and means for opposing the action of said governor device by a force which varies as a function of the range of the target;

11. A tachymetric device according to claim 1 including a motor of the series type having a pair of eld windings for driving the gyroscope rotor, a pair of contacts 'each connected to one of said field windings, a switch'arm extending between and movable into contact with either of said contacts, a governor device operable by said motor and so connected to said switch arm as`to urge it .toward one of said contacts with a force which varies as a function of the speed of said motor, and means for urging said switch arm toward the other vof saidcontacts with a force which varies as a function or the range of the target.

12. A tachymetric correcting device according to claim 1 wherein said iiuid operated servomotor device includes a pilot cylinder, a distribution sleeve slidable within said pilot cylinder, a pilot piston freely slidable within said distribution sleeve, means for supplying a uid under pressure to said pilot vcylinder to act on one side of said pilot piston, adjustable means exerting an equilibrating force on the other side of said pilot piston, a motor piston operatively connected to the element whose position is to be corrected, a cylinder for said motor piston, means including passageways in said pilot piston and distribution sleeve for supplying a iiuid under pressure to one or the other of the sides of said motor piston dependent upon the positions of said pilot piston and distribution sleeve, and means connecting said distribution sleeve to said motor piston for movement therewith. l

13. In a tachymetric correcting device for use in gunnery re control systems of the type wherein the position of an element of the gun laying mechanism is corrected in accordance with the angular velocity of the target observing telescope to compensate for the probable change of position of the target during the time of ilight of the projectile, a iiuid operated servo-motor device for effecting the correcting movement oi' said element including a pilot cylinder, a distribution sleeve slidable within said pilot cylinder, a pilot piston freely slidable within said distribution sleeve, means for supplying a fluid under pressure to said pilot cylinder to act on one side of said pilot piston, adjustable means exerting an equilibrating force on the other side of said pilot piston, a motor piston operatively connected to the element whose position is to be corrected, a cylinder for said motor piston, means including passageways in said pilot piston and distribution sleeve for supplying a iiuid under pressure to one or the other of the sides of said motor piston dependent upon the positions of said pilot piston and distribution sleeve, and means connecting said distribution sleeve to said motor piston for movement therewith, and means for varying the pressure of the iiuid supplied to said servo-motor device in 'accordance with variations in the angular velocity of the target observing telescope.

14. In a tachymetric correcting device foruse in gunnery re control systemsof the type wherein the position of an element of the gun laying mechanism is corrected in accordance with the angular velocity of the target observing telescope to compensate for the probable change of position of the target during the time of flight of the projectile, the combination of a gyroscope so connected with said target observing telescope that the precessional movements thereof are a. measure lfof lthe angular velocity of said telescope, a

' uid operated servo-motor device operatively connected to the element whose position is to be corrected, vand means operatively connectedwith' said gyroscope for controlling the pressure of tli'e iiuid supplied to said servo-motor device, said means being so constructed and arranged that the pressure of the iiuid supplied to said servo-motor device varies as a function of the precevsslonal4 v movements of. said gyroscope.

JEAN FIEUX. 

